Verizon HTC One M8 For Windows On AT&T?

[Windows Central Question]

As far as I can tell, you can't get a new HTC One M8 For Windows from Verizon or T-Mobile without committing to them in some way. I have Cricket service and since they are owned by AT&T my first choice was to wait for it to be available from AT&T. Unfortunately they won't sell me one because I don't use their service. Neither will T-Mobile sell me one of theirs. I am currently in Afghanistan so this wouldn't be an issue if I was stateside. I would still use the phone out here, but I can't because If I buy it outright, it won't be unlocked as far as I know. When I bought my Nokia 1520 I went through similar issues with it with regards to using it overseas. I guess my biggest concern is if I buy a used Verizon phone are the LTE bands going to work for AT&T/Cricket when I get back? I am sort of versed in some of the frequencies and bandwidths so I guess this also may be dependent on my area and the frequencies they've bought or leased in that area Maybe?